The invention relates, in general, to two-stroke internal combustion engines, and, more particularly, to detection of a condition in the combusted fuel-air mixture of two-stroke internal combustion engines.
Various constructions of exhaust gas sensors for internal combustion engines have been heretofore proposed. Various arrangements of internal combustion engines, or portions thereof, employing exhaust gas sensors for air-fuel ratio control in a four-stroke engine have also been heretofore proposed. Typically, exhaust sensors used in four-stroke engine applications function as an electrolytic cell and provide an output signal which depends on oxygen concentration in exhaust gasses produced by the engine, which concentration is measured, for example, at an exhaust pipe.
Direct application of four-stroke engine exhaust sensing techniques to two-stroke engines is not possible due to overscavanging that occurs in two-stroke engines, which overscavanging affects the oxygen concentration in exhaust gasses produced by an engine and flowing through an exhaust pipe.
Attention is directed to the following U.S. Patents which disclose such sensing applications:
______________________________________ U.S. Pat. No. Inventor Issued ______________________________________ 4,225,559 Achari et al. September 30, 1980 4,228,128 Esper et al. October 14, 1980 4,313,810 Niwa et al. February 2, 1982 4,362,605 Bozon et al. December 7, 1982 4,484,440 Oki et al. November 27, 1984 4,617,795 Abthoff et al. October 21, 1986 4,656,830 Ohno et al. April 14, 1987 ______________________________________
Attention is also directed to U.S. patent application Ser. No. 131,449, filed Dec. 11, 1987.
Attention is also directed to SAE Paper 840141, which relates to exhaust sensors.